Iba has a distinctive haircut and wears black sunglasses with his standard Shinigami uniform. He collects sunglasses, mainly from "Silver Dragonfly Glasses Store," the same shop where fellow lieutenant Renji Abarai buys his goggles. Iba also smokes and carries his Zanpakutō as a small blade inside his uniform. His large tattoo on his back features a cat on fire and the kanji for shōfuku (inviting luck), giving him a typical yakuza appearance. His informal speech further reinforces this image.
Despite his tough exterior, Iba is fiercely loyal to his captain. After Kaname Tōsen's betrayal, he spent time at the Eleventh Division headquarters to give his captain space. Before their fight, Ikkaku mentioned that Iba had become more confident since leaving the Eleventh Division to become a lieutenant. Iba also suffers from recurring stomach problems, which he mentions with embarrassment. He shares a working relationship with Ikkaku Madarame, often involving duels, sake drinking, and more dueling to see who must get more drinks.
While not much is known about Iba's Zanpakutō or strength, he is seen frequently in the company of other male lieutenants and seated Shinigami. He shares their interest in perverted things related to female Shinigami. During an encounter with Arrancar Pō, Iba demonstrated his loyalty by refusing to abandon the injured Ikkaku, even when facing overwhelming odds.
Iba enjoys fighting but puts his loyalty to his division above his desire for combat and is willing to retreat if necessary. As president of the Shinigami Men's Association, he forces members to dress like him at meetings. His meetings are often mocked by the Shinigami Women's Association, particularly by vice-president Nanao Ise.
Iba speaks in Hiroshima dialect and once started a course to spread its knowledge, but it failed due to lack of attendance. He now writes an article titled "The Hiroshima Dialect Seminar Brimming with Macho-ism" in Seireitei Communication's "Guys Corner." His favorite food is okonomiyaki, specifically Hiroshima style, while he detests the Osaka style.
Iba originally belonged to the 11th Division but transferred to the 7th Division to achieve lieutenant status, partly to please his mother. Despite leaving, he still frequents the 11th Division headquarters. Though he enjoys a good fight, he prioritizes loyalty over personal ambition. He once lied to his captain before Rukia's execution to give him time to reconsider his decision.
During a confrontation with Kenpachi Zaraki, Iba and Shūhei Hisagi faced off against Ikkaku Madarame and Yumichika Ayasegawa. While sharing sake during their duel, Ikkaku revealed that Iba mastered all elements of Shinigami combat to become a vice-captain. Later, Iba hung out at the Eleventh Division headquarters, noting it was better than being quiet.
When Aizen attacked fake Karakura Town, Iba and his captain defended the area. Iba assisted in stopping Fake Karakura from returning to normal and expressed shock at Pō's released form. After the fight, Iba criticized Ikkaku for not using his Bankai, emphasizing the importance of winning at any cost.
Iba is proficient in both swordsmanship and Kidō, having mastered these skills to become a lieutenant. His sealed Zanpakutō resembles a tantō kept inside his uniform. In Shikai, it transforms into a falchion or large bladed scimitar with a pick-like protrusion. The name and abilities of his Zanpakutō remain unknown, as does its Shikai command. Iba has yet to achieve Bankai.
